A requirement exists for supplying a continuous stream of water at a controlled temperature. One such application is a source of near boiling water in a portable form for use in killing weeds or ant nests, for heating the skin of dead animals so that feathers or hair can be stripped, for wallpaper stripping or for similar purposes. Another application is the provision of water at a substantially constant temperature for washing purposes, e.g. for washing clothes, dishes or hands or in a shower where the temperature should be controlled within plus/minus 1 degree Celsius regardless of flow rate or water pressure.
The apparatus required to do this must avoid some non-obvious problems. Among these is the need for the apparatus not to be orientation sensitive, not to fail disastrously if the supply of water is interrupted, and not to react to air pockets or air bubbles in the water supply or the release of any dissolved gases as the water is heated and to work regardless of the water input temperature.